After the recent death of his son, detective Max Sørensen relocates to Oslo Homicide where he's teamed up with detective Sander Holm. They're sent to a crime scene - four immigrant teenagers drowned in an abandoned swimming pool. The detectives suspect foul play, but eels at the crime scene have a strange effect on the men's psyche. Meanwhile, Max's wife, Asha, begins her new career teaching law at the university, while Sander's mentally disabled brother, Bo, struggles with solitude. Swimming pool owner Thea informs the detectives that a fifth boy was at the pool; the detectives wonder if he's now dead just like the other four. A series of clues lead the men to small-time criminal, Rune Vik. He's distraught. Before killing himself, Rune assures the detectives: the boy is alive.